The present invention relates to object positioning apparatus, in general, and to apparatus for automatically positioning a piece-part in a predetermined orientation for subsequent assembly into a product, in particular.
Automated product assembly machines, for example, have been employed in manufacturing industries for a great number of years. More recently, though, technologically more sophisticated devices have been employed with such machines for such purposes. These more recent devices are commonly referred to as industrial robots. Industrial robots are capable of repetitively performing various mechanical tasks with a high degree of speed and accuracy in response to a set of programmed instructions such as the task of moving a piece-part or workpiece from one position to another as part of a product assembly process.
In order to employ the typical industrial robot in certain portions of an automated assembly process, it is essential that the piece-part be fairly accurately positioned for the robot prior to its initially moving same in order to avoid subsequent piece-part to piece-part misalignment during product assembly resulting from an initial positioning error. While an industrial robot is quite capable of precisely maintaining or changing the orientation of a piece-part when moving the part from one location to another, it is also true that any deviation or error between the desired piece-part orientation where the robot assumes the piece-part to be located and oriented and the actual piece-part location and orientation prior to initial piece-part movement, will also be maintained by the robot throughout piece-part movement because of the robot's inability to detect initial piece-part position and/or orientation errors. Therefore, in order to insure that one piece-part is properly mated to another during product assembly with a minimum of piece-part to piece-part misalignment errors when an industrial robot is employed for such purposes, it is essential that a piece-part be placed as close as possible to a particular initial position and orientation before being moved by the robot. The closer the piece-part to be positioned is placed to said particular initial position and orientation, the smaller will be any piece-part to piece-part misalignment during subsequent product assembly.
Present techniques for positioning a piece-part prior to movement of same by an industrial robot employ the use of such components as a conventional X,Y,.theta. piece-part orienting turntable in conjunction with a piece-part image sensing TV camera and a digital computer in which the physical characteristics of a particular piece-part are stored for subsequent piece-part recognition and orientation purposes. While these techniques are effective for such purposes, computers and TV cameras are relatively expensive items and a computer requires the services of a relatively high-cost computer programmer in order to describe the physical characteristics of each individual piece-part in sufficiently detailed computer language so as to be unambiguously recognized by the piece-part positioning system. In addition, while computerized piece-part positioning systems are able to position piece parts at an acceptable rate of speed for many product assembly applications, their ability to position relatively complex shaped piece-parts at the same acceptable rate of speed or the ability to position less complex shaped piece-parts at high rates of speed is limited.
The primary object of the present invention therefore is to provide low-cost apparatus for rapidly placing randomly oriented, relatively complex shaped objects in a predetermined position and orientation.
Another object of the present invention is to provide means for substantially reducing the time required to describe the characteristics of an object in machine recognizable form for automated object positioning purposes.
A further object of the present invention is to provide means for describing machine recognizable object characteristics that readily allows substitution of the machine recognizable description of one type of object to be positioned for that of another.
Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of the preferred embodiment thereof taken in conjunction with the accompanying drawings.